Machines of the above type are used more and more to ensure bond of superposed sheets or webs, in manner similar to what was initially obtained by so-called sewing machines, joining by means of a needle traversing the materials and bearing a yarn joined with that of a shuttle.
Presently known machines, more particularly reserved for bonding webs or sheets including a proportion of thermoplastic materials, make it possible to produce continuous assemblings of the high-speed welding type allowing mass production of articles of low intrinsic value which may even be reserved for single use.
Such is the case in particular for manufacturing articles for protecting objects or persons in relation with the medical or food domain.
Such articles are being increasingly manufactured from sheets or webs of non-woven materials and, by reason of the welding technique, particularly by ultrasounds, and the high speed of intervention of such machines, the need has been felt to cut, simultaneously and without retake, parallel to the assembly line produced, so as to detach the finished article from an adjacent article or from discarded raw material, in one operation.
Although such a need appears understandable, a condition to seal of such articles must be absolutely respected when the finished articles are intended for use in the medical or food domain.
In order to respond to such a need while respecting such a requirement, it has been recommended to fit, parallel to the counter-head of an assembling machine, a disc capable of being brought under relative pressure against the head, so as to execute the desired cut simultaneously to the assembly line.
The propositions which have been formulated consisted in adapting the disc parallel to one of the faces of the counter-wheel of the counter-head, so as to connect them angularly.
The experiments and tests made have shown that such a proposition does not enable the purpose sought after to be attained in practice due to the fact that the peripheral cutting edge of the disc, cooperating with the wheel of the assembling head, undergoes rapid wear, incompatible with the operating speeds of the presently known machines.
The purpose of the invention is to respond to the need to overcome the shortcomings and inefficiency of the known proposition and, to that end, envisages improvements made to the assembly of the cutting disc of a weld/cut counter-head, so that such a disc may present a cutting efficiency which is in relation with the capacities of continuous linear advance and assembling allowed by the machines for assembling or joining by thermo fusion of the fibers constituting the sheet or web materials ("sheet-type materials") to be assembled or the matter of such sheets or webs.
It is a further object of the invention to render assembly of the cutting disc particularly simple so as periodically to allow a partial dismantling of the counter-head so as to allow partial of total replacement thereof and/or of the disc itself, in the event of defectiveness.